1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of Related Art
Conventionally, in image forming apparatuses such as printers, copy machines, fax machines, and multifunction devices, a surface of a photosensitive drum, is charged by a charge roller, an electrostatic latent image is formed by exposing the photosensitive drum with an LED head, a toner image is formed by electrostatically affixing to the electrostatic latent image a thin layer of toner as developer on a development roller, and the toner image is transferred to paper by a transfer roller. The paper onto which the toner image is transferred is sent to a fusion device by which the toner image is fused to the paper.
In the aforementioned printer, toner that cannot be charged until a regular potential (negative polarity) or toner that is charged with reversed polarity (positive polarity) is generated as fogging toner and affixed to the surface of the photosensitive drum (negative polarity) and then to the paper to cause further fogging. To prevent generation of this fogging toner, the surface potential of the photosensitive drum is set to a potential that makes it difficult for fogging toner to be affixed. (see Japanese Patent Application Publication 2002-169343).
However, in conventional printers, generation of fogging cannot reliably be prevented because the amount of fogging toner generated changes according to the idle time of the printer, the environment in the printer is placed, and the like.